Rotary disc cutting device

ABSTRACT

A device for removing paint or other surface layers from woods, metal, bricks, cement and the like, has a resiliently flexible disc of a moldable material in which a length of a blade of a band saw type is embedded and anchored with its teeth exposed on one face and in which means are also embedded that has an axial member exposed on its other face for use in the attachment of a driver thereto. The embedded blade length is such that is completely encircles the axial means and includes a plurality of loop portions of substantial radial extent with both their leading and trailing courses shown as outwardly inclined in a trailing direction with respect to the direction in which the device is to be rotated by its driver.

Unite States Patent [191 Metz [ Dec. 10, 1974 ROTARY DISC CUTTING DEVICE22 Filed: May 30, 197 211 Appl. No.: 365,222

[52] US. Cl. 15/93, 29/81 J, 144/118 [51] Int. Cl B44d 3/16 [58] Fieldof Search 15/93, 236; 29/78, 95 B,

Primary Examiner-Edward L. Roberts Assistant Examiner-James A. Niegowski[5 7] ABSTRACT A device for removing paint or other surface layers fromwoods, metal, bricks, cement and the like, has a resiliently flexibledisc of a moldable material in which a length of a blade of a band sawtype is embedded and anchored with its teeth exposed on one face and inwhich means are also embedded that has an axial member exposed on itsother face for use in the attachment of a driver thereto. The embeddedblade length is such that is completely encircles the axial means andincludes a plurality of loop portions of sub stantial radial extent withboth their leading and trailing courses shown as outwardly inclined in atrailing direction with respect to the direction in which the device isto be rotated by its driver.

15 Claims, 5 Drawing Figures PATENTEU U59 1 91974 3. 852 843- l ROTARYursc CUTTING DEVICE- BACKGROUND OF THE INVENTION The removal of surfacelayers from such materials as wood, metals, bricks, cement, and the likepresents problems, particularly when such materials are incorporated instructures.

In my co-pending application Ser. No. 234,248, filed March 13, 1972, nowUS. Pat. No. 3,754,297, a con.- tinuation-in-part of now abandonedapplication Ser. No. 107,328, filed Jan. 18, 1971, there are disclosed-molded discs of a flexible material attachable to a de- THE PRESENTINVENTION The objective of the present invention is to provide a devicefor use in treating various surfaces, particularly the removal of paintfrom wood surfaces, the device having a flexible resilient disc with ablade of the band saw type embedded and anchored therein with theembedded blade length in a form that requires a minimum blade length yetis capable of being accurately located in the molded disc and providinga sufficient number of teeth uniformly distributed through asurface-treating zone of adequate radial extent to ensure an effective,uniform attack on the surface.

This objective is attained by providing a blade length as a preform thatis easily handled and that, when embedded and anchored in the flexibleplastic disc to form 1 the device extends completely around the axiallylocated means by which it is secured to a driver and has a plurality ofoutwardly disposed loop portions with at least the leading andpreferably both the leading and trailing courses outwardly inclined in atrailing direction with respect to the direction in which the device isto be rotated and with the closed outer ends of the loop portionsadjacent the periphery of the disc.

Another objective is to provide that the closed, outer ends of the loopportions provide such a curve that the disc has a plurality of teethadjacent its periphery, pref- .erably substantially at the periphery, anarrangement possible because the secure anchorage of the leading andtrailing courses would even permit such closed ends to protrude slightlyfrom the periphery of the disc.

With the looped arrangement of the embedded blade, and with the blade ofthe type having its teeth with cutting edges disposed in the samedirection, the teeth in one course of each loop portion have theircutting edges faced oppositely to those of the other course, preferablythose of the leading course disposed so that at least at and relativelynear-the closed outer end of each loop portion are in cutting direction.As a consequence, the action of the teeth in one course of each loopportion, preferably the trailing course, is an abrading one. With thisarrangement, an adequate cutting action is combined with a substantialabrading action that, in practice, results in the rapid removal of thesurface layer, the bared surfaces in prime condition to receive and holdpaint.

BRIEF DESCRIPTION OF THE DRAWINGS- A preferred embodiment of theinvention is illustrated by the drawings of which FIG. 1 is a plan viewof the work contacting face of i crease in scale, approximately alongthe indicated lines 4-4 of FIG. 1; and

FIG. 5 is a somewhat schematic side elevation of the device in a typicalwork-contacting position.

THE PREFERRED EMBODIMENT The preferred embodiment of the inventionconsists of a resiliently flexible disc 5 of rubber or plastic having alength of a blade 6 therein with its teeth exposed on one face. In orderthat the device may be secured to a suitable portable power operatedtool, not shown, capable of rapidly rotating the device when-heldagainst the work, a socket 7 having a flange 8'is also molded in thedisc 5 with the socket 7 exposed on the otherface thereof.

The socket 7 is threaded either to enable it to be directly secured to athreaded driver with which some such tools, typically commercial types,are provided, or to receive the threaded head 9 of a stem 10 thus toenable the device to be attached to a driving too] having a chuck. Y

While the disc'5 may be formed from any elastomeric material that has asufficient degree of resilient flexibility, a solid cast or slightlyexpanded cast polyurethane elastomeric material using either thepolyester or the polyether types are most satisfactory. Polyester vinylchloride plastisol may also be used. Desirably a disc 6 inches indiameter is in the approximate thickness range of 3 to /8 inch range andhas a hardness factor in the approximate range of as determined with adurometer.

- The blade 6 is a preform with the ends of the blade length overlappedand welded together at 6A and shaped and dimensioned to encircle thesocket 7 with a series of outwardly disposed loop portions, generallyindicated at 11, and providing leading courses l lA, trailing courses11B and closed outer ends 11C. The leading and trailing courses are bothoutwardly inclined in a trailing direction with respect to the directionin which the device is rotated by its driver, the direction indicated bythe arrow in FIG. 1. The overlapped junction 6A of the blade ends isshown as located in a trailing course 118. Best results are attainedwhen the courses are curved in said trailing direction and in any event,the closed outer ends are close tothe periphery of the disc 5, thedistance between them and said periphery being desirably in the order ofone-eighth inch or less.

For best results in treating wood surfaces, the number of teeth per inchof blade length is 14 as commercially available blade stock with eitherfewer or more teeth per inch is either too coarse or too fine for mostuses.

The loop portions 11 must be spaced at least apart but the use of six,equally spaced such portions of the band saw type embedded is preferredas ensuring the provision of a sufficient number of teeth for theeffective attack of the surface layer to be removed. In practice, theblade length required to form such a preform is in the neighborhood of29 inches in the case of a 6'inch disc.

It is preferred that the blade stock used be of a type in which itsteeth 12 are all disposed to cut when the blade is linearly advanced inone direction and the preferred arrangement of the preform is to havethe teeth in the closed outer ends of the loop portions 1] disposed in acutting direction when the device is rotated by its driver. With thisarrangement, the teeth in the leading courses 11A have an appreciablecutting effect while those in the trailing courses 11B are reversedrelative thereto and have primarily an abrasive action and usually thepoints of the teeth of the two courses are slightly offset radially. Inpractice, each blade length is formed with a series of longitudinallyspaced slots 13 ensuring its thorough anchorage in the disc 5.Desirably, see FIG. 4, the base of the teeth 12 are positioned slightlyabove the proximate face of the disc to facilitate the discharge ofparticles from under the disc 5 and the disposition of heat. Withone-half inch blade stock, the preferred disc thickness is approximatelythreeeighths inch with about one-sixteenth of an inch of the bladeexposed to space, the base of the teeth from the proximate face of thedisc, the height of the teeth being about one-sixteenth of an inch. Theother edge of the blade is just within the other face of the disc, seeFIG. 4.

It will be appreciated that, more often than not, the devices are heldagainst the work with their axes tilted slightly from the normalrelative thereto, typically with, if the device were not rotating, thesegment defined by the chord l4 and its subtended minor arc in contactwith the work. While the embedded blade 6 stiffens the disc 5, itsdisposition permits a sufficient degree of flexibility to ensure thatthe loop portions successively lay flat against the work with the driveaxis thus tilted with the result that the unwanted surface iseffectively at tacked and removed leaving the wood or other surface inideal condition to be repainted or stained.

Devices in accordance with the present invention combine ease ofassembly, a unique combination of cutting and abrading actions, and anadequate degree of flexibility.

. I claim:

1. A device for use in removing paint or other surface layers from wood,metal, bricks, and the like and to be rotated by a power driver, saiddevice comprising a resiliently flexible disc of a moldable material, alength of a blade of the band saw type embedded and anchored in the discin such a manner that its teeth are exposed on a face thereof, and axialmeans exposed on the other face for attaching the disc' to the driver,said embedded blade length extending completely around said axial meansand including'a plurality of outwardly disposed loop portions providingleading and trailing courses and closed outer ends, at least the leadingcourse of each loop portion being outwardly inclined in a trailingdirection with respect to the direction the device is to be rotated,said loop portions being of substantial and radial extent and uniformlyspaced circumferentially.

2. The device of claim 1 in which the arcuate space between the outerends of the loop portions is less thanv 3. The device of claim 1 inwhich the arcuate space between the outer ends of the loop portion is60.

I 4. The device of claim 1 in which the junctions of the loop portionsare close to the axial means.

5. The device of claim 1 in which the outer ends of the projections aresubstantially at the periphery of the disc.

6. The'device of claim 1 in which the trailing course of each loopportion is also outwardly inclined in a trailing direction.

7. The device of claim 1 in which the leading course of each loopportion is outwardly curved towards its closed end in a trailingdirection.

8. The device of claim 7 in which the trailing courses are curved in thesame manner as the leading courses.

9. The device of claim 1 in which the courses of each loop portion areof the same. length.

10. The device of claim 1 in which the blade is of the type having teethdisposed to cut to the maximum extent when moved linearly in onedirection and to the minimum extent when moved linearly in the oppositedirection and the blade is disposed so that the teeth in the closed endsof the loop portions are in their cutting direction with at least theouter portions of the leading courses operative to provide a cuttingattack on the surface with action of the teeth of the trailing coursebeing primarily an abrading one.

11. The device of claim 10 in which the number of teeth per inch ofblade length being in the neighborhood of fourteen. I

12. The device of claim 10 in which each course is curved outwardly in atrailing direction.

13. The device of claim 1 in which the closed outer end of each loopportion is rounded with a portion located so closely to the periphery ofthe disc that the maximum distance separating said closed end and saidperiphery is in the neighborhood of one-eighth inch.

14. The device of claim 1 in which the hardness of the disc material asmeasured by a durometer is in the approximate range of 85, the discthickness is about three-eighths inch-and the blade stock is one-halfinch and the embedded blade length positions the base of the teeth abovethe proximate face of the disc.

15. The device of claim 14 in which the distance between the base of theteeth and said proximate face is about one-sixteenth of an inch.

1. A device for use in removing paint or other surface layers from wood,metal, bricks, and the like and to be rotated by a power driver, saiddevice comprising a resiliently flexible disc of a moldable material, alength of a blade of the band saw type embedded and anchored in the discin such a manner that its teeth are exposed on a face thereof, and axialmeans exposed on the other face for attaching the disc to the driver,said embedded blade length extending completely around said axial meansand including a plurality of outwardly disposed loop portions providingleading and trailing courses and closed outer ends, at least the leadingcourse of each loop portion being outwardly inclined in a trailingdirection with respect to the direction the device is to be rotated,said loop portions being of substantial and radial extent and uniformlyspaced circumferentially.
 2. The device of claim 1 in which the arcuatespace between the outer ends of the loop portions is less than 90*. 3.The device of claim 1 in which the arcuate space between the outer endsof the loop portion is 60*.
 4. The device of claim 1 in which thejunctions of the loop portions are close to the axial means.
 5. Thedevice of claim 1 in which the outer ends of the projections aresubstantially at the periphery of the disc.
 6. The device of claim 1 inwhich the trailing course of each loop portion is also outwardlyinclined in a trailing direction.
 7. The device of claim 1 in which theleading course of each loop portion is outwardly curved towards itsclosed end in a trailing direction.
 8. The device of claim 7 in whichthe trailing courses are curved in the same manner as the leadingcourses.
 9. The device of claim 1 in which the courses of each loopportion are of the same length.
 10. The device of claim 1 in which theblade is of the type having teeth disposed to cut to the maximum extentwhen moved linearly in one direction and to the minimum extent whenmoved linearly in the opposite direction and the blade is disposed sothat the teeth in the closed ends of the loop portions are in theircutting direction with at least the outer portions of the leadingcourses operative to provide a cutting attack on the surface with actionof the teeth of the trailing course being primarily an abrading one. 11.The device of claim 10 in which the number of teeth per inch of bladelength being in the neighborhood of fourteen.
 12. The device of claim 10in which each course is curved outwardly in a trailing direction. 13.The device of claim 1 in which the closed outer end of each loop portionis rounded with a portion located so closely to the periphery of thedisc that the maximum distance separating said closed end and saidperiphery is in the neighborhood of one-eighth inch.
 14. The device ofclaim 1 in which the hardness of the disc material as measured by adurometer is in the approximate range of 75 - 85, the disc thickness isabout three-eighths inch and the blade stock is one-half inch and theembedded blade length positions the base of the teeth above theproximate face of the disc.
 15. The device of claim 14 in which thedistance between the base of the teeth and said proximate face is aboutone-sixteenth of an inch.